Changes in the physicochemical quality of rainbow trout's High pressure (HP)treated at 220, 250 and 330 MPa, 7, 15 and 25 degrees C for 5 and 10 min were investigated. HP-treated rainbow trout's showed significantly increased L* value relative to untreated rainbow trout's. Little changes in colour (a* value) were observed, compared to untreated rainbow trout's, which did not showed b* values. From tests of chemical properties, HP-treated rainbow trout's did not showed or showed significantly decreased thiobarbituric acid (TBA) and trimethylamine nitrogen (TMA-N) with increasing treatment pressure compared to controls. HP-treated rainbow trout samples showed significantly increased or decreased free amino acids (P < 0.05) relative to untreated trout samples. The results obtained from this study showed that the quality of HP-treated rainbow trout is best preserved at 220 MPa, 7-15-25 degrees C for 5-10 min and 250 MPa, 7-15 degrees C for 5 min.